A 61 year old man with a 1.5 year history of eosinophilia (absolute eosinophil count up to 32x10⁹) undergoes a third bone marrow biopsy. Prior laboratory studies to evaluate for the etiology of eosinophilia have been negative. The current specimen reveals absolute eosinophilia with cytologic atypia on peripheral smear and bone marrow aspirate, a hypercellular bone marrow with megakaryocyte atypia.  Blasts are not increased. Cytogenetics revealed 46 XY del(3)(q21 )[19/20].

	Andres Madrigal, M.D., Ph.D. Resident, Hematopathology Mayo Clinic
	Min Shi, M.D., Ph.D. Consultant, Hematopathology Mayo Clinic Assistant Professor of Laboratory Medicine and Pathology Mayo Clinic College of Medicine

A 55-year-old female with history of eating disorder and high output ileostomy presented with electrolyte abnormalities, dehydration, chronic kidney failure, and severe QT prolongation. Initial serum lab evaluation revealed severe hypokalemia, hypochloremia, and hypermagnesemia. Stool studies revealed an osmotic cause of diarrhea with fecal osmotic gap of 204 mOsm/kg. Fecal sodium, potassium, chloride, magnesium, and phosphorous were 41 mmol/L, 2 mmol/L, 127 mmol/L, 231 mg/dL, and 3 mg/dL, respectively.

	Kornelia Galior, Ph.D. Resident, Clinical Chemistry Mayo Clinic
	Darci Block, Ph.D. Consultant, Laboratory Medicine and Pathology Mayo Clinic Assistant Professor of Laboratory Medicine and Pathology Mayo Clinic College of Medicine